A fitting portion for connecting a wiring substrate with a connector of another device conventionally has a structure in which a portion of conductive circuits that are formed on one surface of the substrate are exposed, with contact points of the connector side brought into contact with the exposed portions of the conductive circuits to be electrically connected, as shown in FIG. 8A and FIG. 8B. In the fitting portion of this wiring substrate 91, in addition to reducing the diameter of the connection by miniaturization and thinning of the device, fine pitching of the conductive circuits 92 is increasingly progressing.
However, there is a risk of easily causing electrical faults between adjacent conductive circuits by narrowing the wiring interval of the conductive circuits 92 and fine pitching of the conductive circuits 92 and the portions 92a that make contact with the contact point of the connector.
Also, when the size of the conductive circuit at the portion that makes contact with the contact point of the connector is reduced and fine pitching of the conductive circuits is performed, then as shown in FIG. 9 if a shift occurs in which the connectors 86 move slightly in the wiring width direction W, the disadvantage easily occurs in which each connector 86 separates from the exposed surface 83a of the conductive circuit 83, and so an electrical connection cannot be made between the connectors 86 and the conductive circuits 83.
Also, in the case of the constitution of FIG. 8A, there is known a wiring substrate that is provided with a covering layer 105 that is formed by coating a migration resistant resin (a paste material) on the outer periphery of a printed circuit portion 102 that is formed on the upper surface of a wiring substrate 101 in order to suppress migration resistance, as shown in FIG. 10. In the case of this substrate structure, when fine pitching is performed, due to the accuracy of the printing, there is a risk of the side surface portion of the printed circuit being exposed because a sufficient covering layer cannot be formed. When the printing circuit is exposed, migration readily occurs, which becomes an impediment to fine pitching.
Patent Document 1: Japanese Unexamined Patent Application, First Publication No. H06-132057